System and method for characterizing bioreactor fluids

ABSTRACT

A magnetic resonance device for monitoring growth of tissue in one or more bioreactors. The device can include a first magnet and a second magnet that can form a uniform magnetic field of desired strength around at least one sample of effluent from at least one bioreactor. At the command of a controller, an RF signal can illuminate the at least one magnetized sample, and sensors can detect at least one echo signal from the at least one magnetized sample. The controller can characterize the at least one sample based on the at least one echo signal. A resonator can shape the at least one echo signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 62/593,408, filed Dec. 1, 2017, entitled SYSTEM AND METHOD FORCHARACTERIZING BIOREACTOR FLUIDS, and U.S. Provisional Application Ser.No. 62/701,251, filed Jul. 20, 2018, entitled SYSTEM AND METHOD FORCHARACTERIZING BIOREACTOR FLUIDS, which are incorporated herein byreference in their entireties.

BACKGROUND

The present teachings relate generally to tissue engineering, and morespecifically to systems and methods to monitor tissue growth.

Magnetic resonance can be used to characterize the composition ofmaterials by taking advantage of the different resonant frequencies ofmolecular structures. Nuclear magnetic resonance (NMR) involves applyinga magnetic field to the material, and the composition of the materialdetermines the frequency of the resonance. When resonance is achieved,the material is illuminated for a short time with a radio frequency (RF)signal at the frequency of the resonance. When the material isilluminated, the material absorbs some of the signal's energy. Whenthere is no illumination, the material will echo some of the absorbedenergy back out. The echo can be used to identify the material. Bysystematically adjusting the magnetic field gradient and signal's pulsewaveform, the echo can be converted into an image that enables tissuemonitoring. NMR devices can be any size. Smaller NMR devices can includepermanent magnets and can be used to measure high-resolution NMRspectra. Advances in real-time magnetic resonance techniques can be usedto detect moving fluid as it passes through the magnetic field of themagnetic resonance apparatus. Real-time magnetic resonance techniquesinclude continuous data acquisition and iterative reconstruction, andcan be used to create a differenced picture of the temporal variation ofthe tissue growth based on effluent flowing through a growing tissueenclosure.

Currently, desktop NMR devices weigh between about 42 pounds and 375pounds. A lighter device, geared for production settings, can becost-effective to build and use. A device that can analyze multiplesamples simultaneously can enable rapid tissue analysis.

SUMMARY

Systems and methods for characterizing tissue samples from, for example,but not limited to, a bioreactor, can include magnet configurations suchas magnets that are positioned by rotation, and magnets that arepositioned by lateral movement. Magnet positioning, in conjunction withmagnetic field spreaders, can provide a stable magnetic field from whichreliable measurements can be taken.

The apparatus of the present teachings of a first configuration foridentifying contents of effluent from at least one tissue bioreactor caninclude, but is not limited to including, a rotatable magnet, and atleast one container including the effluent. The at least one containercan be positioned in proximity to the rotatable magnet. The apparatuscan include a second magnet positioned in proximity to the at least onecontainer. The second magnet can be positioned to form a magnetic fieldacross the effluent. The apparatus can include an adjustment means thatcan rotate the rotatable magnet to adjust the strength of the magneticfield, and a transmitter that can periodically transmit a non-ionizingsignal across the magnetized effluent. The non-ionizing signal canenergize the magnetized effluent. The apparatus can include a receiverreceiving a first at least one echo signal from the magnetized energizedeffluent based on the non-ionizing signal, and a controller controllingthe transmitter, the receiver, and the adjustment means by means ofcommands. The controller can characterize the first at least one echosignal, and can identify the contents of the effluent based on thecharacterized first at least one echo signal. The apparatus canoptionally include a steel block positioned in proximity to the secondmagnet. The rotatable magnet can optionally include a cylindrical shape.The apparatus can optionally include a spreader that can be operablypositioned between the rotatable magnet and the second magnet. Thespreader can enable uniformity of the magnetic field. The rotatablemagnet can optionally include a diametric magnetization vector. Thediametric magnetization vector can be substantially perpendicular to thespreader. The apparatus can optionally include a resonator that canshape the transmitted non-ionizing signal. The apparatus can optionallyinclude a resonator that can shape the received echo signal. Theapparatus can optionally include a positioner that can adjust thestrength of the magnetic field based on the position of the secondmagnet. The positioner can optionally respond to the commands from thecontroller. The non-ionizing signal can optionally include an RF signal.The apparatus can optionally include an electronic signal generator. Thesignal generator can supply the non-ionizing signals, and can respond tothe commands from the controller. The adjustment means can optionallyinclude a stepper motor. The apparatus can optionally include atemperature sensor that can provide temperature data to the controller.The controller can command the signal generator to adjust, based on thetemperature data, the center frequency of the electronic signal toaccommodate magnetic drift.

The method of the present teachings for a first configuration forcharacterizing at least one sample from at least one bioreactor using amagnetic resonance apparatus, where the magnetic resonance apparatusincludes a first magnet and a second magnet, and where the first magnetand the second magnet are positioned to set up a magnetic field, themethod can include, but is not limited to including, determining adesired magnetic field strength for the magnetic field, rotating thefirst magnet and positioning the second magnet to achieve the desiredmagnetic field strength, circulating the at least one sample in themagnetic field, periodically illuminating the at least one sample withan electronic signal, sensing a first at least one echo signal betweenthe illuminations, and characterizing the at least one sample based onthe first least one echo signal. The first magnet can optionally includea diametric magnetization vector. The diametric magnetization vector canbe substantially perpendicular to a spreader. The spreader canoptionally include operable coupling with the second magnet. Theelectronic signal can travel a first path, and the first path caninclude at least one tank circuit, at least one coil, and the at leastone sample. The method can optionally include directing the at least oneelectronic signal using the at least one tank circuit. The electronicsignal can optionally include an RF signal. The at least one echo signalcan optionally travel a second path. The second path can optionallyinclude at least one tank circuit and at least one coil. The method canoptionally include rotating the first magnet to achieve a changedmagnetic field strength and a changed magnetic field, circulating the atleast one sample through the changed magnetic field, periodicallyilluminating the at least one sample with the electronic signal, sensinga second at least one echo signal between the illuminations, andcharacterizing the at least one sample based at least on a comparisonbetween the second at least one echo signal and the first least one echosignal. The characterizing can optionally include envelope detection andcurve fit.

The system of the present teachings of a second configuration forcharacterizing at least one sample from at least one bioreactor caninclude, but is not limited to including, an enclosure forming a pathfor a magnetic field. The enclosure can include a plurality of cavitiesthat can accommodate a first magnet, a second magnet, a firstpositioning means, a second position means, a first slug, and a secondslug. The first magnet and the second magnet can be positioned apre-selected distance from one another within two of the cavities. Thefirst slug can positioned between the first magnet and the enclosure.The first slug and the second slug can include including magneticmaterial, and the second slug can be positioned between the secondmagnet and the enclosure. The system can include a controller that cancontrol the first positioning means and the second positioning means toposition the first slug and the second slug to shape the uniformity ofthe magnetic field using variable reluctance to create a uniformmagnetic field. The controller can enable circulation of the at leastone sample in the magnetic field. The sample can be associated with atleast one coil. The controller can periodically illuminate the at leastone sample and the at least one coil with an RF signal. The controllercan sense at least one echo signal between the illuminations, and thecontroller can characterize the at least one sample based on the sensedleast one echo signal. The system can optionally include a position lockmeans fixing the positions of the first slug and the second slug whenthe uniform magnetic field is achieved. The system can optionallyinclude a sample tube encircled by the at least one coil. The sampletube can rest between the first magnet and the second magnet, and canprovide a channel for the at least one sample. The system can optionallyinclude non-stick material surrounding the first slug and the secondslug. The system can optionally include non-stick material surroundingthe first slug and the second slug and a resonator shaping the at leastone echo signal.

The method of the present teachings of a second configuration forcharacterizing at least one sample from at least one bioreactor using amagnetic resonance apparatus, where the magnetic resonance apparatus caninclude a first magnet and a second magnet, and where the first magnetand the second magnet can be positioned a pre-selected distance from oneanother to set up a magnetic field, and where the first magnet and thesecond magnet can be positioned within an enclosure forming a path forthe magnetic field, the method can include, but is not limited toincluding, positioning a first slug between the first magnet and theenclosure, and positioning a second slug between the second magnet andthe enclosure. The first slug and the second slug can include magneticmaterial. The method can include shaping the uniformity of the magneticfield using variable reluctance, to create a uniform magnetic field, byadjusting the positions of the first slug and second slug. The methodcan include circulating the at least one sample in the uniform magneticfield. The sample can be associated with at least one coil. The methodcan include periodically illuminating the at least one sample and the atleast one coil with an electronic signal, sensing at least one echosignal between the illuminations, and characterizing the at least onesample based on the sensed least one echo signal. The method canoptionally include fixing the positions of the first slug and the secondslug when the uniform magnetic field is achieved. The at least one coilcan optionally be about 1 mm in thickness. The at least one sample canoptionally be enclosed in a glass tube, the glass tube can optionally beencircled by the at least one coil, and the glass tube can optionallyrest between the first magnet and the second magnet. The pre-selecteddistance between the first magnet and the second magnet can optionallymeasure about 0.3 inches. The first slug and the second slug canoptionally be surrounded by a non-stick material. The method canoptionally include manually positioning the first slug and the secondslug. The method can optionally include automatically positioning thefirst slug and the second slug. The method can optionally includeautomatically circulating the at least one sample, automaticallyperiodically illuminating the at least one sample, automatically sensingthe at least one echo signal, and automatically characterizing the atleast one sample.

The method of the present teachings for a third configuration forcharacterizing at least one sample from at least one bioreactor using amagnetic resonance apparatus, where the magnetic resonance apparatusincludes a first magnet and a second magnet, and where the first magnetand the second magnet are positioned to set up a magnetic field, themethod can include, but is not limited to including, determining adesired magnetic field strength for the magnetic field, rotating thefirst magnet and positioning the second magnet to achieve the desiredmagnetic field strength, circulating the at least one sample in themagnetic field, periodically illuminating the at least one sample withan electronic signal, sensing a first at least one echo signal betweenthe illuminations, and characterizing the at least one sample based onthe first least one echo signal. The first magnet can optionally includea diametric magnetization vector. The diametric magnetization vector canbe substantially perpendicular to a spreader. The spreader canoptionally include operable coupling with the second magnet. Theelectronic signal can travel a first path, and the first path caninclude at least one antenna, at least one resonator, at least one coil,and the at least one sample. The at least one resonator can bephysically isolated from the at least one antenna. The at least oneresonator can include, but is not limited to including, at least onetank circuit. The method can optionally include directing the at leastone electronic signal using the at least one resonator. The electronicsignal can optionally include an RF signal. The at least one echo signalcan optionally travel a second path. The second path can optionallyinclude at least one resonator and at least one coil. The method canoptionally include rotating the first magnet to achieve a changedmagnetic field strength and a changed magnetic field, circulating the atleast one sample through the changed magnetic field, periodicallyilluminating the at least one sample with the electronic signal, sensinga second at least one echo signal between the illuminations, andcharacterizing the at least one sample based at least on a comparisonbetween the second at least one echo signal and the first least one echosignal. The characterizing can optionally include envelope detection andcurve fit.

The method of the present teachings of a fourth configuration forcharacterizing at least one sample from at least one bioreactor using amagnetic resonance apparatus, where the magnetic resonance apparatus caninclude a first magnet and a second magnet, and where the first magnetand the second magnet can be positioned a pre-selected distance from oneanother to set up a magnetic field, and where the first magnet and thesecond magnet can be positioned within an enclosure forming a path forthe magnetic field, the method can include, but is not limited toincluding, positioning a first slug between the first magnet and theenclosure, and positioning a second slug between the second magnet andthe enclosure. The first slug and the second slug can include magneticmaterial. The method can include shaping the uniformity of the magneticfield using variable reluctance, to create a uniform magnetic field, byadjusting the positions of the first slug and second slug. The methodcan include circulating the at least one sample in the uniform magneticfield. The sample can be associated with at least one coil. The methodcan include periodically illuminating the at least one sample and the atleast one coil with an electronic signal, sensing at least one echosignal between the illuminations, and characterizing the at least onesample based on the sensed least one echo signal. The method canoptionally include directing the electronic signal using a resonator.The at least one coil can optionally include about 1 mm in thickness.The method at least one sample can optionally be enclosed in a glasstube, and the glass tube can optionally be encircled by the at least onecoil. The glass tube can optionally rest between the first magnet andthe second magnet. The pre-selected distance between the first magnetand the second magnet can optionally include about 0.3 inches. The firstslug and the second slug can optionally be surrounded by a non-stickmaterial. The method can optionally include manually positioning thefirst slug and the second slug. The method can optionally includeautomatically positioning the first slug and the second slug. The methodcan optionally include controlling the circulating, illuminating,sensing, and characterizing with an automatic controller.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will be more readily understood by reference tothe following description, taken with the accompanying drawings, inwhich:

FIG. 1 is a schematic block diagram of the first configuration of themagnetic resonance system of the present teachings;

FIG. 1A is a schematic block diagram of a second configuration of themagnetic resonance system of the present teachings;

FIG. 1B is a schematic block diagram of the matrix of coils of thepresent teachings;

FIG. 2 is a perspective diagram of the first configuration of themagnetic resonance system of the present teachings;

FIG. 2A is an exploded perspective diagram of the first configuration ofthe magnetic resonance system of the present teachings;

FIG. 3 is a perspective diagram of the first configurations of themagnetic resonance system of the present teachings including a radiofrequency apparatus and a bioreactor tube;

FIG. 3A is a perspective diagram of the coil of the present teachings;

FIG. 3B is a side view of the first configuration of the magneticresonance system of the present teachings;

FIG. 3C is an overhead perspective view of the first configuration ofthe magnetic resonance system of the present teachings;

FIG. 3C-1 is a circuit diagram of a configuration of the tank circuit ofthe present teachings;

FIG. 3D is a perspective diagram of the effluent passage of the firstconfiguration of the magnetic resonance system of the present teachings;

FIG. 4 is a flowchart of the method for characterizing effluent of thepresent teachings;

FIG. 5 is a schematic block diagram of the first configuration of themagnetic resonance system of the present teachings;

FIGS. 6A-6D are perspective and exploded diagrams of the secondconfiguration of the magnetic resonance system of the present teachings;

FIG. 7 is a pictorial representation of the magnetic field produced bythe magnetic resonance system of the present teachings; and

FIG. 8 is a flowchart of the method for characterizing effluent of thepresent teachings.

DETAILED DESCRIPTION

Referring now to FIG. 1, system 100 can provide a cost-effective way tomonitor effluent characteristics continuously. In some configurations,effluent from a tissue growth system can be characterized by exposing atleast one sample from, for example, bioreactor 111 to magnetic resonancethrough, for example, nuclear magnetic resonance (MR) system 101. Insome configurations, MR system 101 can include two magnets forming amagnetic field surrounding the effluent. In some configurations, firstmagnet 117 can be adjusted by magnet adjustment means 115 to form auniform magnetic field. In some configurations, first magnet 117 caninclude a rotating magnet, and adjustment means 115 can include, but isnot limited to including, a stepper motor. By adjusting first magnet117, the field strength between first magnet 117 and second magnet 119can be adjusted, which can likewise adjust the frequency of theresonance of sample 123. In some configurations, the strength of themagnetic field can be ≥0.3 T.

Continuing to refer to FIG. 1, system 100 can include magnetic fieldstrength sensor 105 that can provide information about the magneticfield to controller 103. Controller 103 can adjust first magnet 117based at least on the data provided by magnetic field strength sensor105, and the adjustment can alter the strength of the magnetic field.System 100 can include temperature sensor 107 that can providetemperature data of MR system 101 to controller 103. Controller 103 candetermine, for example, magnetic drift based on the temperature data,and can adjust the center frequency of RF signal 121 generated by RFgenerator 113 to accommodate the magnetic drift. Uniformity of themagnetic field can cause the precession of enough electrons so that thecombined energy will be able to be seen on a spectrum analyzer. Theprecession frequency of the electrons can indicate the characteristicsof the sample according to Larmor's equation: f₀=γ B₀, where f₀ is theprecession frequency of the electrons in the sam3le, B₀ is the strengthof the magnetic field surrounding the sample, and γ is the gyromagneticratio, a constant specific to each nucleus or particle. The value of γfor an exemplary particle such as, for example, but not limited to ¹H,is 42.58. Negative values for γ indicate that the direction ofprecession for the nucleus or particle is opposite the direction ofprecession of ¹H. The resonance frequency of any particle at a certainfield strength can be calculated using the Larmor equation. For example,for ¹H, when B₀=1.5 T, f₀=42.58 Mhz/T*1.5 T=63.87 Mhz.

Referring now to FIG. 1A, in some configurations, system 100A caninclude sample sensors 109-1 through 109-n that can receive informationabout constituents of effluent stream 123 that can, for example, cyclethrough bioreactor 111-1. Sample sensors 109-1 through 109-n can providesample information to controller 103, and controller 103 can determinecharacteristics of the constituents. In some configurations, one samplesensor 109-1 can receive and process information about the entireeffluent stream. In some configurations, multiple bioreactor streams 123can emerge from multiple bioreactors 111-1 through 111-n and can besimultaneously analyzed. Multiple bioreactor streams 123 can beilluminated by a single RF coil, and can each be associated with an RFreceiver. A resonator can be shaped to direct the signal from the sampleto the proper receiver so that controller 103 can associate a samplewith a signal.

Referring now to FIG. 1B, system 100B can include a matrix of coils thatcan be formed to receive and process information from multiplebioreactor streams simultaneously. The bioreactor streams can originatefrom a single bioreactor or from multiple bioreactors 5111A-5111H, forexample. Multiple streams 6111 can flow through a single MR system 5101Aor multiple MR systems 5101A-5101H, for example. Any number of MRsystems and bioreactors can be ganged together with any number ofswitches, not limited to including three switches and eight MR systems,which numbers and configurations set out herein are exemplary only. MRcontrol/data signals 6113A from MR systems 5101A-5101D can be routedthrough first switch 5161 and second switch 5167, and MR control/datasignals 6113B from MR systems 5101E-5101H can be routed through thirdswitch 5163 and second switch 5167. First switch 5161 and third switch5163 can include four poles each, and can be operably coupled withsecond switch 5167, which can include two poles, providing for each ofeight MR/bioreactor pairs to be separately controlled, depending uponthe orientation of the poles in first switch 5161, second switch 5167,and third switch 5163. Other configurations can include, but are notlimited including, multiple bioreactor streams flowing into a single MRsystem, where the single MR system can multiplex signals from themultiple bioreactor streams.

Referring now primarily to FIGS. 2 and 2A, MR apparatus 5600, aconfiguration of MR system 100 (FIG. 1), can include rectangular magnet5605, a configuration of magnet 2 119 (FIG. 1) and cylindrical magnet5609, a configuration of magnet 1 117 (FIG. 1). Rectangular magnet 5605and cylindrical magnet 5609 can be mounted upon platform 5603, and canbe chosen to optimize magnetic field strength to enable the use ofrelatively small magnets to obtain a relatively large amount ofinformation from the effluent that travels through specimen mount 5635.In some configurations, cylindrical magnet 5609 can measure 1.5″ indiameter and one inch in height, but magnet 5609 is not limited to thesemeasurements. With respect to creating a desired magnetic field, magnet5605 can be moved towards magnet 5609 by installation screw 5637 (FIG.2A) that can enable controlled placement of magnet 5605 regardless ofmagnet strength. In some configurations, installation screw 5637 (FIG.2A) can be operably coupled with controller 103 (FIG. 1), and can movemagnet 5605 in accordance with data obtained from magnetic fieldstrength sensor 105 (FIG. 1). A magnet rotation system can enablerotation of cylindrical magnet 5609 to adjust the magnetic field. Insome configurations, the magnet rotation system can be operably coupledwith controller 103 (FIG. 1), and can rotate magnet 5609 in accordancewith data obtained from magnetic field strength sensor 105 (FIG. 1). Themagnet rotation system can include, but is not limited to including,strength adjustment means mount 5611 that can securely mount poleadjuster 5615, and link lever arm 5613 upon which pole adjuster 5615 canrest as it is rotated. Pole adjuster 5615 can operably couple withswivel yoke 5619 (FIG. 2A) that can disable rotational adjustment ofmagnet 5609 at pre-selected settings. Cylindrical magnet mount 5607 canoperably couple with alignment pin 5621 (FIG. 2A) and mount guide cavity5614 (FIG. 2A) that can together enable proper vertical placement ofcylindrical magnet 5609. At least one effluent tube 5627 (FIG. 3) can besecurely positioned within specimen mount 5635. In some configurations,multiple bioreactors 111-1 through 111-n can produce separate streams ofeffluent and can require multiple effluent tubes 5627 (FIG. 3). Specimenmount 5635 can include multiple effluent tubes 5627 (FIG. 3), and canaccommodate the geometry of magnet 5609 and at least one spreader 5617.At least one spreader 5617 can enable uniformity in the magnetic field,based on the geometry of the magnets and specimen mount 5635.

Continuing to refer to FIGS. 2 and 2A, in some configurations, poleadjuster 5615 can be a screw, and can, in conjunction with link leverarm 5613, perform high resolution rotation of magnet 5609. In someconfigurations, a desired angular resolution can be chosen, for example,but not limited to, ±0.025°. A combination of thread pitch and distanceof lever arm 5613 can be chosen so that magnet 5609 can be rotated inincrements smaller than the desired angular resolution if a reasonableminimum articulation angle is chosen, for example, 1/16 of a revolution.In some configurations, when the minimum adjustment is chosen to be 16°,the minimum sweep adjustment, as a fraction of a revolution, is16°/360°. In some configurations, pole adjuster 5615 is a screw having a3/16-inch thread diameter and 100 threads/inch. Dividing the minimumsweep adjustment by the threads/inch yields displacement/minimumadjustment, or 0.0004 inches/thread. The angular rotation can becalculated as:

arcsin ((displacement/minimum adjustment)/length of lever arm 5613)

In some configurations, the length of lever arm 5613 can beapproximately 2.435 inches, and the angular rotation can equal0.01050094°. In some configurations, system 5600 can include parts thatcan, collectively, weigh approximately ten pounds, and can bemanufactured economically, for example, for under 500 USD. In someconfigurations, system 5600 can optionally include a connector betweenspreader 5617 (FIG. 3B) and sink 5601 (FIG. 3) that can retain theposition of spreader 5617 (FIG. 3B).

Referring now to FIGS. 3, and 3A-3D, energy from a known magnetic fieldcan be applied to an effluent, and a transmitting coil can pulse thenon-ionizing RF signal across the effluent. The pulsed non-ionizing RFsignal can excite the nuclear spin energy transition of the effluent.The gradient of the magnetic field can be uniform within the measuredbandwidth. The magnetic field can surround the effluent that cancirculate through a bioreactor (not shown) in effluent tube 5627 (FIG.3). The bioreactor can include growing tissue, for example. RFtransmitter 5657 (FIG. 3) can supply an RF signal to a transmitter coil,for example, coil 5651 (FIG. 3A), cabled to power by cable 5653 (FIG.3A), through at least one transmitter tank circuit 5621/5623/5625 (FIG.3C), depicted schematically in FIG. 3C-1. At least one transmitter tankcircuit 5621/5623/5625 (FIG. 3C) can be adjusted electronically usingvoltage controlled varactor tuning, for example, to enable driftcorrection. The choice of the frequency of the RF signal is based uponthe atomic structure of the sample and the magnetic field. The magneticfield orients the atoms in the sample, and the pulsing RF signal acrossthe sample makes the atoms resonate at a characteristic frequency thatdepends on the magnetic field strength. In some configurations, ashielded cable from the source of the RF signal and/or from the sensorto the coil can be included, with the tank circuit oriented in betweenthe sample and the coil. When the RF signal ceases pulsing, thereceiving coil can detect the echo from the sample. In someconfigurations, a single coil can be used to both transmit and receivethe RF signal, and can be adjusted electronically as shown in FIG. 3C-1.

Referring now to FIG. 3B, the space between magnets 5605 and 5609affects the magnetic field strength. In some configurations, magnet 5609can include a diametric magnet whose diametric magnetization vector canextend from the center of magnet 5609 to the ridge of spreader 5617. Insome configurations, magnets 5605/5609 can be chosen such that themagnetic field set up by magnets 5605/5609 can measure approximately 1.2Tesla, and can have approximately a 501 b pull force. Spreader 5617 canbe chosen such that the magnetic field, when including spreader 5617,can measure approximately 0.9 Tesla. In some configurations, spreader5617 can adjust the uniformity of the magnetic field across the sample,and the amount of the adjustment can depend on the geometry of spreader5617. Spreader 5617 can include a single unit, or can include multipleunits, possibly operably coupled. In some configurations, the shape ofspreader 5617 can accommodate the geometry of specimen mount 5635.

Referring now to FIG. 3C, at least one transmitter tank circuit5621/5623/5625 (FIG. 3C) can be constructed to tune the RF signal to aparticular frequency. As the effluent circulates near a transmittingcoil, for example, but not limited to, coil 5651 (FIG. 3A), which emitsnon-ionizing electromagnetic energy received from RF transmitter 5657(FIG. 3), and tuned by at least one transmitter tank circuit5621/5623/5625, the effluent in effluent tube 5627 (FIG. 3) can respondto the RF signal. The sample's response to the signal can be received bya receiving coil connected to RF receiver 5655 (FIG. 3) via the shieldedcable, and tuned by at least one tank circuit 5621/5623/5625. Thereceived tuned signal can be processed by a controller (not shown) togather data about the effluent. The contents of the effluent can bedetermined, for example, based on Larmor's equation. There can be anynumber of tank circuits between RF receiver 5655 (FIG. 3) and thereceiving coil, and between RF transmitter 5657 (FIG. 3) and thetransmitting coil. The tank circuits can include geometries that areselected to shape the signal strength of the magnetic field. Tankcircuits can be used to, for example, but not limited to, focus anddirect the RF signal.

Referring now to FIG. 3C-1, circuit 5400 can include coil 5411 andcapacitor 5409, along with varactor 5413, that can form an LC-resonanttank circuit. Coil 5411 forms the inductive portion, and capacitor 5409combined with varactor 5413 form the capacitive portion. Varactor 5413,when reverse biased with a DC voltage 5003, entering circuit 5400through positive and negative terminals 5406/5407, will behave as acapacitor, with the amount of capacitance controlled by the DC voltagepotential. In this arrangement, the resonant frequency of the LC tankcircuit can be changed by adjusting the DC voltage on the varactor. Inclose proximity (approximately 0.1-0.5 inches) to the LC resonantcircuit, inductors 5403A and 5403B provide a high impedance at the LCtank resonant frequency, while maintaining a low DC resistance to thevaractor control voltage. Similarly, capacitor 5401 provides a highimpedance for the varactor control voltage, and a low impedance at theLC tank resonant frequency. In this arrangement, inductors 5403A and5403B, along with capacitor 5401 can decouple the LC circuit from the DCcontrol voltage circuit. An alternating current electromagnetic energysignal propagating through a non-conductive medium such as, for example,but not limited to, air, foam, or ceramic, in close proximity(approximately 0.1-0.5 inches) to coil 5411 will induce a voltage incoil 5411, creating a storage charge. The charge will continue to growin potential, additionally charging the capacitive portion formed bycapacitor 5409 combined with varactor 5413, until the AC signal reversespolarity. When the AC signal reverses polarity, the stored charge in theinductive portion will flow into the capacitive portion, and vice-versa.The resonant frequency of the LC tank circuit is now controlled by anexternal DC voltage. Current flowing through coil 5411 back and forth tothe capacitive portion of the LC tank circuit will create a secondarymagnetic field. This field, by virtue of the geometry of coil 5411 andproximity to transmit and receive coils, for example, coil 5651 (FIG.3A) of MR system 5635 (FIG. 3A), can be used to shape the transmitsignal into the sample, and the received echo signal from the sample.

Referring now to FIG. 4, method 150 for characterizing at least onesample from at least one bioreactor using a magnetic resonanceapparatus, the magnetic resonance apparatus having a first magnet and asecond magnet, the first magnet and the second magnet positioned to setup a magnetic field, the method can include, but is not limited toincluding, determining 151 a desired magnetic field strength for themagnetic field, rotating 153 the first magnet and positioning the secondmagnet to achieve the desired magnetic field strength, circulating 155the at least one sample in the magnetic field, periodically illuminating157 the at least one sample with an electronic signal, sensing 159 atleast one echo signal between the illuminations, and characterizing 161the at least one sample based on the sensed least one echo signal.

Referring now to FIG. 5, system 5100 can provide a cost-effective way tomonitor effluent characteristics continuously. In some configurations,effluent from a tissue growth system can be characterized by exposing atleast one sample from, for example, bioreactor 5111 to magneticresonance through, for example, nuclear magnetic resonance (MR) system5101. The sample can be conveyed through the magnetic field by a samplecarrier (not shown) that can be associated with coil 118. Coil 118 caninclude a resonator such as, for example, but not limited to, a tankcircuit. In some configurations, MR system 5101 can include two magnetsforming a magnetic field surrounding the effluent. In someconfigurations, first magnet 5117 and second magnet 5119 can eachinclude a first side and a second side. The first side of each of firstmagnet 5117 and second magnet 5119 can be mounted adjacent to enclosuressuch as, for example, but not limited to, first enclosure 5217 (FIG. 6A)and second enclosure 5204 (FIG. 6A). The second side of each of firstmagnet 5117 and second magnet 5119 can be at least partially covered byfield spreaders such as, for example, but not limited to, first spreader5215 (FIG. 6C) and second spreader 5201 (FIG. 6C). In someconfigurations, the distance between first spreader 5215 (FIG. 6C) andsecond spreader 5201 (FIG. 6C) can be approximately 0.1-0.8 inches. Themagnetic field spreaders can, in conjunction with first reluctance pathobstruction 5118A and second reluctance path obstruction 5118B, create auniform magnetic field as first reluctance path obstruction 5118A andsecond reluctance path obstruction 5118B positions are adjusted. Firstreluctance path obstruction 5118A and second reluctance path obstruction5118B can be adjusted by moving first slug 517A and second slug 519Atowards or away from first magnet 5117 and second magnet 5119,respectively. Slug adjustment means 5115 can be used to move first slug517A and second slug 519A. In some configurations, slug adjustment means5115 can be manual. Slug adjustment means 5115 can include, but is notlimited to including, knob 5211 (FIG. 6A). In some configurations, slugadjustment means can be controlled by controller 5103, either locallyand/or remotely.

Continuing to refer to FIG. 5, system 5100 can include magnetic fieldsensor 5105 that can provide information about the magnetic field tocontroller 5103. Controller 5103 can adjust the position of first slug517A and second slug 519A based at least in part on data from magneticfield sensor 5105. Controller 5103 can adjust the center frequency of RFsignal 121 and can receive and process RF echo signals 124 from thesample. The information about the magnetic field can include, but is notlimited to including, strength and uniformity. In some configurations,the strength of the magnetic field can be a function of the position ofthe resonator, the size of the sample carrier, and the proximity of themagnetic field to the sample carrier. In some configurations, theresonator is optional.

Continuing to refer to FIG. 5, in some configurations, echo signal 124can provide sample information to controller 5103, and controller 5103can determine characteristics of the constituents. In someconfigurations, echo signal 124 can include information from multiple ofbioreactors 5111, and controller 5103 can be simultaneously analyzetheir data. Multiple of bioreactors 5111 can each be associated with,for example a separate RF receiver. At least one transmitter tankcircuit (not shown) can be constructed to tune the RF signal to aparticular frequency. As the effluent circulates near a transmittingcoil, emitting non-ionizing electromagnetic energy received from RFtransmitter 5121, and tuned by at least one transmitter tank circuit(not shown), the effluent in the effluent tube (not shown) can respondto RF signal 121. The sample's echo 124 resulting from RF signal 121 canbe received by a receiver coil and RF echo receiver 5123, and tuned byat least one tank circuit (not shown). The received tuned signal can beprocessed by controller 5103 to gather data about the effluent. Thecontents of the effluent can be determined, for example, based onLarmor's equation. There can be any number of tank circuits between theRF receiver and the receiving coil, and between the RF transmitter andthe transmitting coil. The tank circuits can include geometries that areselected to shape the signal strength of the magnetic field. Transmitter5121 and echo receiver 5123 can be combined so that the RF signal 121and echo 124 originate and terminate at the same transceiver.

Referring now primarily to FIGS. 6A-6D, system 5101A, a configuration ofsystem 5100 (FIG. 5), can include magnet 5216, a configuration of firstmagnet 5117 (FIG. 5), and magnet 5205, a configuration of second magnet5119 (FIG. 5). Magnet 5216 and magnet 5205 can be chosen to optimizemagnetic field strength and uniformity to enable the use of relativelysmall magnets to obtain a relatively large amount of information fromthe effluent that travels through a specimen tube (not shown) resting inspecimen mount 5203/5209. In some configurations, magnets 5205/5216 canbe rectangular in shape, and can measure about 4″×2″×0.25″. Other magnetsizes and shapes are possible. With respect to creating a magnetic fieldof desired uniformity and strength, slug 5214 can be moved towardsmagnet 5205, and slug 5222 can be moved towards magnet 5216, therebyadjusting the reluctance obstruction path. In some configurations, thumbscrews 5211 can be used to adjust the positions of slugs 5214/5222. Theselection of the number and type of thumb screws 5211, or automaticmagnet positioning adjuster (not shown), can be based at least in parton the strength of magnets 5205/5216. In some configurations, to enablethe movement of slugs 5214/5222 during adjustment, slugs 5214/5222 canbe surrounded by non-stick material, such as, for example, but notlimited to, a material coated with a TEFLON® finish. Any number of slugsand magnets can be used, as long as a uniform magnetic field of thedesired strength is created. In some configurations, slugs 5214/5222 canbe held in place by fasteners such as, for example, but not limited to,c-clips. At least one effluent tube (not shown) can be securelypositioned within specimen mounts 5203/5209. Any form of stabilizationfor the effluent tube can be used. In some configurations, multiple ofbioreactors 5111 (FIG. 5) can produce separate streams of effluent andcan require multiple effluent tubes (not shown). Specimen mounts5203/5209 can accommodate multiple effluent tubes (not shown) and canaccommodate the geometry of magnetic field path 5301 (FIG. 7). Spreaders5201/5215 can enable uniformity in the magnetic field across the sample,and the amount of the adjustment can depend on the geometry of spreaders5201/5215. Spreaders 5201/5215 can include a single unit, or can includemultiple units, possibly operably coupled. In some configurations, theshape of spreaders 5201/5215 can accommodate the geometry of specimenmounts 5203/5209. In some configurations, system 5101A can include partsthat can, collectively, weigh approximately ten pounds, and can bemanufactured economically, for example, for under 500 USD. A magneticfield path can be formed by frame elements 5223/5224/5202/5212/5213(FIG. 6D). The shape and thickness of frame elements5223/5224/5202/5212/5213 (FIG. 6D), and their relationship to oneanother, can vary depending on the desired shape and size of the frame.In some configurations, elements 5223/5224/5212/5213 (FIG. 6D) canoverlap elements 5202 (FIG. 6D) at both ends.

Referring now to FIG. 7, energy from uniform magnetic field 5301 can beapplied to an effluent, and a transmitting coil can pulse non-ionizingwaves across the effluent. The pulsed non-ionizing waves can excite thenuclear spin energy transition of the effluent. The gradient of uniformmagnetic field 5301 can be uniform within the measured bandwidth, andcan localize the resulting signal in space. Uniform magnetic field 5301can surround the effluent that can circulate through bioreactor 5111(FIG. 5) and the effluent tube (not shown). Bioreactor 5111 (FIG. 5) cansurround growing tissue, for example. RF transmitter 5121 (FIG. 5) cansupply RF signal 121 (FIG. 5) to a transmitter coil (not shown). Thechoice of the frequency of RF signal 121 (FIG. 5) can be based upon theatomic structure of the sample and uniform magnetic field 5301. Uniformmagnetic field 5301 orients the atoms in the sample, and pulsing RFsignal 121 (FIG. 5) across the sample makes the atoms resonate at acharacteristic frequency that depends on the magnetic field strength.When RF signal 121 (FIG. 5) ceases pulsing, receiver 5123 can detectecho signal 124 (FIG. 5) from the sample.

Referring now to FIG. 8, method 5150 for characterizing at least onesample from at least one bioreactor using a magnetic resonanceapparatus, the magnetic resonance apparatus having a first magnet and asecond magnet, the first magnet and the second magnet positioned apre-selected distance from one another to set up a magnetic field, thefirst magnet and the second magnet positioned within an enclosureforming a path for the magnetic field, the method can include, but isnot limited to including, positioning 5151 a first slug between thefirst magnet and the enclosure. The first slug can include magneticmaterial. Method 5150 can include positioning 5153 a second slug betweenthe second magnet and the enclosure. The second slug can includemagnetic material. Method 5150 can include shaping 5155 the uniformityof the magnetic field using variable reluctance, to create a uniformmagnetic field, by adjusting the positions of the first slug and secondslug. Method 5150 can include circulating 5157 the at least one samplein the uniform magnetic field. The sample can be associated with atleast one coil. Method 5150 can include periodically illuminating 5159the at least one sample and the at least one coil with an electronicsignal, sensing 5161 at least one echo signal between the illuminations,and characterizing 5163 the at least one sample based on the sensedleast one echo signal.

Configurations of the present teachings are directed to computer systemsfor accomplishing the methods discussed in the description herein, andto computer readable media containing programs for accomplishing thesemethods. The raw data and results can be stored for future retrieval andprocessing, printed, displayed, transferred to another computer, and/ortransferred elsewhere. Communications links can be wired or wireless,for example, using cellular communication systems, militarycommunications systems, and satellite communications systems. Parts ofsystem 100 (FIG. 1), system 100A (FIG. 1A), system 100B (FIG. 1B), andsystem 5100 (FIG. 5), for example, can execute on a computer having avariable number of CPUs. Other alternative computer platforms can beused.

The present configuration is also directed to hardware, firmware, andsoftware for accomplishing the methods discussed herein, and computerreadable media storing software for accomplishing these methods. Thevarious modules described herein can be accomplished by the same CPU, orcan be accomplished on a different computer. In compliance with thestatute, the present configuration has been described in language moreor less specific as to structural and methodical features. It is to beunderstood, however, that the present configuration is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the present configurationinto effect.

Methods 150 (FIG. 4) and 5150 (FIG. 8), can be, in whole or in part,implemented electronically. Signals representing actions taken byelements of system 100 (FIG. 1), system 100A (FIG. 1A), system 100B(FIG. 1B), and system 5100 (FIG. 5), for example, and other disclosedconfigurations can travel over at least one live communications network.Control and data information can be electronically executed and storedon at least one computer-readable medium. The systems can be implementedto execute on at least one computer node in at least one livecommunications network. Common forms of at least one computer-readablemedium can include, for example, but not be limited to, a floppy disk, aflexible disk, a hard disk, magnetic tape, or any other magnetic medium,a compact disk read only memory or any other optical medium, punchedcards, paper tape, or any other physical medium with patterns of holes,a random access memory, a programmable read only memory, and erasableprogrammable read only memory (EPROM), a Flash EPROM, or any othermemory chip or cartridge, or any other medium from which a computer canread. Further, the at least one computer readable medium can containgraphs in any form, subject to appropriate licenses where necessary,including, but not limited to, Graphic Interchange Format (GIF), JointPhotographic Experts Group (JPEG), Portable Network Graphics (PNG),Scalable Vector Graphics (SVG), and Tagged Image File Format (TIFF).

While the present teachings have been described above in terms ofspecific configurations, it is to be understood that they are notlimited to these disclosed configurations. Many modifications and otherconfigurations will come to mind to those skilled in the art to whichthis pertains, and which are intended to be and are covered by both thisdisclosure and the appended claims. It is intended that the scope of thepresent teachings should be determined by proper interpretation andconstruction of the appended claims and their legal equivalents, asunderstood by those of skill in the art relying upon the disclosure inthis specification and the attached drawings.

What is claimed is:
 1. A method for characterizing at least one samplefrom at least one bioreactor using a magnetic resonance apparatus, themagnetic resonance apparatus having a first magnet and a second magnet,the first magnet and the second magnet positioned to set up a magneticfield, the method comprising: determining a desired magnetic fieldstrength for the magnetic field; rotating the first magnet andpositioning the second magnet to achieve the desired magnetic fieldstrength; circulating the at least one sample in the magnetic field;periodically illuminating the at least one sample with an electronicsignal; sensing at least one echo signal between the illuminations; andcharacterizing the at least one sample based on the sensed least oneecho signal.
 2. The method as in claim 1 further comprising: rotatingthe first magnet to achieve a changed magnetic field strength and achanged magnetic field; circulating the at least one sample in thechanged magnetic field; periodically illuminating the at least onesample with the electronic signal; sensing a second at least one echosignal between the illuminations; and characterizing the at least onesample based at least on a comparison between the second at least oneecho signal and the sensed least one echo signal.
 3. The method as inclaim 2 wherein the characterizing comprises envelope detection andcurve fit.
 4. An apparatus for identifying contents of effluent from atleast one tissue bioreactor comprising: a rotatable magnet; at least onecontainer including the effluent, the at least one container positionedin proximity to the rotatable magnet; a second magnet positioned inproximity to the at least one container, the second magnet positioned toform a magnetic field across the effluent, magnetizing the effluent; anadjustment means rotating the rotatable magnet to adjust the strength ofthe magnetic field; a transmitter periodically transmitting at least onenon-ionizing signal across the magnetized effluent, the at least onenon-ionizing signal energizing the magnetized effluent; a receiverreceiving at least one echo signal from the magnetized energizedeffluent based on the at least one non-ionizing signal; and a controllercontrolling the transmitter, the receiver, and the adjustment means bymeans of commands, the controller characterizing the at least one echosignal, the controller identifying the contents of the effluent based onthe characterized at least one echo signal.
 5. The apparatus as in claim4 further comprising: a spreader operably positioned between therotatable magnet and the second magnet, the spreader enabling uniformityof the magnetic field.
 6. The apparatus as in claim 5 wherein therotatable magnet comprises a diametric magnetization vector, thediametric magnetization vector being substantially perpendicular to thespreader.
 7. The apparatus as in claim 4 further comprising: a resonatorshaping the transmitted at least one non-ionizing signal.
 8. Theapparatus as in claim 4 further comprising: a resonator shaping thereceived at least one echo signal.
 9. The apparatus as in claim 4further comprising: a positioner adjusting the strength of the magneticfield based on a position of the second magnet.
 10. The apparatus as inclaim 9 wherein the positioner responds to the commands from thecontroller.
 11. The apparatus as in claim 4 further comprising anelectronic signal generator, the generator supplying the at least onenon-ionizing signal, the generator responding to the commands from thecontroller.
 12. The apparatus as in claim 11 further comprising: atemperature sensor providing temperature data to the controller, thecontroller commanding the transmitter to adjust, based on thetemperature data, a center frequency of the electronic signal toaccommodate magnetic drift.
 13. A method for characterizing at least onesample from at least one bioreactor using a magnetic resonanceapparatus, the magnetic resonance apparatus having a first magnet and asecond magnet, the first magnet and the second magnet positioned apre-selected distance from one another to set up a magnetic field, thefirst magnet and the second magnet positioned within an enclosureforming a path for the magnetic field, the method comprising:positioning a first slug between the first magnet and the enclosure, thefirst slug including magnetic material; positioning a second slugbetween the second magnet and the enclosure, the second slug includingmagnetic material; shaping the uniformity of the magnetic field usingvariable reluctance, to create a uniform magnetic field, by adjustingthe positions of the first slug and the second slug; circulating the atleast one sample in the uniform magnetic field, the at least one samplebeing associated with at least one coil; periodically illuminating theat least one sample and the at least one coil with an electronic signal;sensing at least one echo signal between the illuminations; andcharacterizing the at least one sample based on the sensed least oneecho signal.
 14. The method as in claim 13 further comprising: directingthe electronic signal using a resonator.
 15. The method as in claim 13wherein the pre-selected distance between the first magnet and thesecond magnet comprises about 0.3 inches.
 16. The method as in claim 13wherein the first slug and the second slug are surrounded by a non-stickmaterial.
 17. The method as in claim 13 further comprising: controllingthe circulating, illuminating, sensing, and characterizing with anautomatic controller.
 18. A system method for characterizing at leastone sample from at least one bioreactor comprising: an enclosure forminga path for a magnetic field, the enclosure including a plurality ofcavities accommodating a first magnet, a second magnet, a firstpositioning means, a second positioning means, a first slug, and asecond slug, the first magnet and the second magnet positioned apre-selected distance from one another within two of the cavities, thefirst slug positioned between the first magnet and the enclosure, thefirst slug including magnetic material, the second slug positionedbetween the second magnet and the enclosure, the second slug includingmagnetic material; and a controller controlling the first positioningmeans and the second positioning means to position the first slug andthe second slug to shape the uniformity of the magnetic field usingvariable reluctance to create a uniform magnetic field, the controllerenabling circulation of the at least one sample in the magnetic field,the at least one sample being associated with at least one coil, thecontroller periodically illuminating the at least one sample and the atleast one coil with an RF signal, the controller sensing at least oneecho signal between the illuminations, and the controller characterizingthe at least one sample based on the sensed least one echo signal. 19.The system as in claim 18 further comprising: a sample tube encircled bythe at least one coil, the sample tube resting between the first magnetand the second magnet, the sample tube providing a channel for the atleast one sample.
 20. The system as in claim 18 further comprising: aresonator shaping the at least one echo signal.